Gas mask canister



Oct. 3, 1939. A. M. PRENTISS GAS MASK GANISTER Filed July 19, 1953 INVENTOR. fluausr/xv M/Qii/WZSIS 00BD a o a Fig.2

ATTORNEY.

Patented o... a, 1939 PATENT OFFICE 10 Claims.

(Granted under the act "or March a, 1883, as amended Apr-i130, 192s; 370 o. c. 751) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of anyroyalty thereon.

This invention relates to apparatus-for filtering and purifying air containing noxious gases and smokes and more particularly to canister used in connection with gas masks.

In orderto render air contaminated with gases and smokes fit for-breathing, it has been the practice to use a gas mask having a canister associated therewith, whereby all inhaled air -must first pass through the canister wherein it is filtered and purified. Such canister should have a maximum efficiency in cleansing the air of gases and smokes; it should be light in weight and compact; and it shouldbe as inexpensive to manufactureand assemble as possible.

One object of this invention is to generally improve the construction of canisters used with gas masks.

Another object of this invention is to simplify and cheapen the construction of gas mask canisters without lowering the efficiency thereof.

Another object of this invention is to lower the resistance to breathing of a gas mask canister without decreasing its efliciency.

' These and other objects of this invention will be apparent from the following description and claims, it being understood that the several necessary elements comprising the invention may be varied in construction, proportion and arrangement without departing from the spirit of the invention and the scope of the appended claims.

In order to make the invention more clearly understood, the accompanying drawing shows means for carrying the same into practical effect,

- without limiting the improvements in then-useful applications to the particular constructions which, for the purpose of explanation, have been made the subject of illustration.

In the drawing Fig. 1 is a part sectional part elevational view of a preferred form of canister.

tion and in elevation. 1

56 a lower cover 2 crimped Into tight engagement Fig. 2 is a bottom view thereof, partly in secwith casing I, and having a central opening in which is positioned the inlet valve structure. The inlet valve comprises a plate 3 having openings 4 therein. A rubber fiap valve 5 is secured to plate 3 by a central rivet and normally closes openings 4. I

The casing I is adapted to contain the filtering and purifying agents for the air. A top cover .6 is adapted to telescope over the casing I and be sealed thereto by adhesive tape 1. Covert has a central opening through which passes threaded sleeve Bhaving an outwardly turned flange 9 on its inner end. An angled nipple II is threaded on sleeve 8, the opposite end of the nipple being adapted to receive a rubber or can'- vas hose leading to the gas mask. The inner edges of cover 6 and an auxiliary inner cover I2 are clamped between flange 9 and nipple II.

Inner cover I2 has its outer edge crimped over a cup-shaped filter I3. This filter is made up of cotton linters sucked on a perforated form while in a plastic mass and then dried and removed from the form. Filter I3 is of the same configuration as and is spaced slightly from the casing I and bottom closure 2. The cup-shaped filter I3 serves as a combined filter for gases and smokes and container for granular or powdered chemicals N which serve to purify air passing therethrough.

Inner cover I2 has an opening through which the chemicals It may be introduced into filter it. This opening is then closed by a tightly fitting cover I5.

Crimped over the flange 9 of sleeve 8 and supported thereby is a flared hollow member I 6, the lower portion thereof being oval in cross section. Secured to this oval portion as by rivets I! is a perforated oval member I8 having its lower side walls I9 bent into engagement and secured together. In order to prevent the'entrance of the granular chemicals into member I8,

athin cotton bag 2I is positioned over member I8 and is secured thereto as by adhesive tape The cup-shaped filter element I3 when made as above described has sufficient inherent stability to withstand the necessary handling in the filling and assembly operations. I

The par-ts of the canister are assembled by first securing the cup filter I3 to the inner cover I2, and securing the flange 9 of sleeve 8 to the inner cover I2 and flared member IS. The

chemicals I4 are theninserted into filter I3 through the opening in cover I2 and this opening is then tightly closed by cap it. Quter cover 6 isthen positioned over sleeve 8 and outlet nipple ii is threaded-on sleeve 8, the threads being preferably coated with hot marine glue and heated before screwing into place. This assembly is then inserted into casing i which has the bottom 2 secured thereto.

When nipple II is connected to a gas mask hose, air may enter through fiap valve 5 and then pass through the bottom or sides of filter l3. Fil r i3 removes the smoke particles from the air and the chemicals ll, such as activated charco 1 and soda lime, cleanse the air of injurious gas s. The pure air then passes through the perforations in member l8 and into the outlet nipple ii.

By the use of the cup-shaped filter iii, the outer perforated metal sleeve is eliminated and the resistance to air fiow is lowered by affording a larger area through which the inspired air may pass.

Although an important feature of this invention is the provision of substantially cup-shaped filter which is inherently self-supporting and contains the chemicals, it will be clear that the irivention is not limited to a filter having a bottom of sucked-on cotton linters. The bottom may be of sheet metal, plain or perforated, and secured to the sides of filter l3 by crimping similar to the securing of inner cover thereto, or any other securing means. Furthermore, the cupshaped filter may be made of other materials than the sucked-on cotton linters herein described,.

such as wool, fur, hair, fiber, or a mixture of these.

While I have shown and described one preferred embodiment of the invention it will be understood that the invention is not limited thereto, since many variations will occur to those skilled in the art within the scope of the appended claims.

I claim:-

1. A canister for 'gas masks comprising an outer container having an air inlet and an air outlet, a fibrous, substantially cup-shaped filter element containing air cleansing means, and means to support said filter element out of con- .tact with the side walls and bottom of said container, said filter element being inherently selfsus aining and having unitary bottom and sidewal s.

2. A canister for gas masks comprising an outer con ainer having an air inlet and an air outlet, a fibrous, substantially cup-shaped filter element having unitary bottom and side walls and supported by its rim out of contact with the walls and bottom of said container, and filtering material in said filter element.

3. A canister for gas masks comprising an outer container, a fibrous, substantially cup-shaped filter element having unitary bottom and side s walls therein, a cover for closing the top of said said filter element, and an air inlet for said container. I

4. A canister for gas masks comprising an outer container having an air inlet and an air outlet, an inner cover and an outer cover connected together, a cup-shaped filter element having its rim secured to said inner cover and supported solely by said cover, said outer cover being secured to said container, granular filtering material in said filter element, said filter element being formed with integral bottom and side walls of fibrous material which is self-supporting.

5. A canister for purifying air comprising an outer container, a cup-shaped filter element therein formed of fibrous material spaced from the wall of said container, air purifying means within said filter element, and an inlet and an outlet for said casing so arranged that entering air must pass through said filter element and the air purifying means therein prior to its passage out of said outlet, characterized in that the filter element is self-sustaining and is unsupported by a perforated screen.

6. A canister for purifying air comprising an outercontainer having an air inlet and an air outlet, a cup-shaped filter element therein spaced from the wall and bottom of said container, air purifying material in said filter element, characterized in that the filter element is entirely formed of fibrous material and is self-sustaining;

7. A canister for purifying air comprising an outer container having an air inlet and an air outlet, a cup-shaped filter element therein spaced from the bottom and side walls of said container, air-purifying material in said filter element, characterized' in that the filter element is formed of cotton linters and being sufficiently stiff to retain its shape when partially filled with chemicals formed of fibrous material and being sufficiently stifl'v to retain its shape when partially filled with chemicals and suspended from its open rim.

9. As a new article of manufacture, a filter element for use in gas mask canisters and having a low resistance to passage of air therethrough comprising a substantially cup-shaped member formed of cotton linters and being sumciently stiff to retain its shape when partially filled'with chemicals and suspended from its open rim.

10. A canister for gas masks comprising an outer container having an air inlet and an air outlet, a substantiallycup-shaped filter element having its bottom and side walls formed entirely of fibrous material, air purifying means within said filter element, and means to support said filter element with its side walls and bottom out of contact with the outer container, whereby the superficial area of the filter element is increased with a corresponding decrease in breathing resistance with no increase in the size of the outer container.

AUGUSTIN M. PRENTISS. 

